I Tried Intermittent Fasting for a Week

Well, a few weeks actually. I’ve been experimenting with Intermittent Fasting on and off for a few weeks already. But, I haven’t really focused on whether or not this practice could affect my weight loss goal. So now is the time to do that, but before I get into the gritties let’s back up and talk about what Intermittent Fasting is.

What is Intermittent Fasting?

Many diet plans will tell you to count your calories, measure your food, exercise more, and tell you what you eat. Basically the idea is always if you take in less calories than you need you will lose weight: calories in and calories out. The idea is to always have a calorie deficit that would allow you to drop a pound or two a week. So if I know I need 3,000 calories a day and I can cut 500 calories per day from my diet that I know I would have a calorie deficit per week of 7 * 500 = 3,500 calories. So I could limit my calories to 2,500 per day (3,000 – 500) through diet or exercise and I should lose about a pound a week since a pound of fat is about 3,200 calories.

Intermittent Fasting takes a different approach, while still producing an overall calorie deficit. Instead of focusing on what and how much you eat, Intermittent Fasting focuses on when you eat. You will agree to feeding and fasting windows. For example, you may agree to only eat from 11AM to 7PM each day or you might eat normally five days a week and not eat at all for two days a week. So your fasting time could be Tuesday and Thursday and your feeding time would be Sunday, Monday, Wednesday, Friday, and Saturday.

There are reasons why I’m interested in this technique, some of which are simply practical and some which may be deeper than that. But it’s complicated and that topic will have to wait for a later post.

Intermittent Fasting Has Surprised Me

A few weeks ago I started with Intermittent Fasting by doing a few 16:8 days here and there. That means I only ate during an eight hour window and then fasted for the remaining 16 hours each day. Practically speaking this meant that I skipped breakfast and didn’t snack after dinner. After I got some confidence with that I tried to insert a 36 hour fast in here and there. I did this this maybe once or twice. My experience with fasting has really surprised me.

I wasn’t really as hungry as I thought I would be and I generally felt fine during both types of fasts. In fact, during the longer 36 hour fasts I felt more mentally clear and had much more energy than I normally would. On top of that I ended up having a lot of extra free time on my hands because I didn’t need to plan and cook meals, do dishes, or make those last minute grocery store runs.

My reaction to fasting was so positive that I decided to incorporate this practice into my routine. I honestly thought about this before but I just never thought it was something that I could do. And there are other myths that prevented me from seriously considering fasting including: you shouldn’t miss breakfast, fasting will reduce your metabolism, fasting with result in muscle loss. According to some experts, fasting is superior to other forms of calorie reduction for weight loss.

Dialing In Weight Measurements

There is a lot more to say about Intermittent Fasting and the other lifestyle adjustments that you can make. For me, Intermittent Fasting is only part of an overall strategy that includes eating more healthy foods (leafy greens in particular) and avoiding processed foods (they are like mainlining pounds).

The purpose of this post today is to try and figure out when I should record my weight of record. I know that my weight can fluctuate at least five pounds from my true weight in either direction depending on time of day and what I have eaten in the past few days. And we also know that health weight loss is around 1-3 pounds per week which is less than natural fluctuation. Depending on when I weight myself it could looked like I have lost or gained 10 pounds even though there has been no change. Worse, I could be in reality losing weight but the scale might report that I’m gaining weight.

Yet, I need have feedback and be able to know that I’m on track with my efforts. I need this both for motivation but also so I can figure out if I need to make changes.

What’s the solution? The best thing to do is make sure to always weigh yourself at the same time and on the same day of the week. This makes week to week or month to month comparisons more accurate. In the past for me I used to weigh myself on Fridays because it signaled the end of my workout week. But I found that my measurements were artificially low and so I moved to weighing myself on Wednesday.

The idea is that Wednesday is distant enough from the weekend to negate any artificial bloating from the weekend’s sins but not too low to record after five days of intense workouts. The fasting schedule follows a similar pattern so Wednesday still seems like a good choice, but I worry that the previous day with it’s 36 hour fast will give an artificially low reading.

So what I’m doing for the next few weeks is recording each day’s fasting plan and each day’s weight taken at 6:30AM. I’ll do this for about three weeks to see if there are any dramatic differences that would throw off my measurements. Here’s what I got:

SundayCheat Day
Monday16:8 Fast
Tuesday36 Hour fast
Wednesday16:8 Fast318.1
Thursday36 Hour fast318.1
Friday16:8 Fast313.9
SaturdayCheat Day316.7
SundayNormal Day324.5
Monday16:8 Fast326.4
Tuesday36 Hour fast322.0
Wednesday16:8 Fast315.5
Intermittent Fasting Schedule and Short Term Results

Conclusion (For Now)

I think that mid-week weigh-ins every two weeks or at the end of every month is the best thing to do. This is enough to track progress without overwhelming yourself with measurement fatigue.

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Matt is the author of five Apress books including Learn RStudio IDE, Quick, Effective, and Productive Data Science, Objective-C Recipes, Swift Quick Syntax Reference, Objective-C Quick Reference, and the upcoming Pro Data Visualization with R and JavaScript. He has over 20 years of experience in technology, psychometrics, and data analytics working in major higher education institutions such as The College Board and Educational Testing Service. He has earned a Master’s degree in Information Systems Management and a Bachelor’s degree in Quantitative Psychology.